High dose of darunavir in treatment-experienced HIV-infected adolescent results in virologic suppression and improved CD4 cell count

Second- and Third-line Antiretroviral Therapy for Children and Adolescents: A Scoping Review

BACKGROUND

The World Health Organization identified a need for evidence to inform revision of second- and third-line antiretroviral therapy (ART) options in children failing ART. We performed an in-depth scoping review of all available literature on second-line and subsequent ART regimens in children younger than 18 years.

METHODS

We comprehensively searched, without language or date limitations, the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, the World Health Organization's International Clinical Trials Registry Platform and ClinicalTrials.gov.

RESULTS

The search retrieved 1982 records. Eighteen studies provided efficacy data: 1 randomized controlled trial, 7 phase II trials, 5 prospective and 5 retrospective cohorts. Five studies evaluated regimens in children failing first-line ART, 4 in children with multidrug resistance and 9 in children with variable treatment experience. Only 10/18 studies reported week 48 or month 12 outcomes. The overall proportion of children with virologic suppression defined by study at week 48 was 61.8%. Although the randomized controlled trial had low risk of bias, outcomes were similar between groups because of highly active optimized background regimens. All phase II and prospective studies were judged to have moderate to high risk of bias. No study compared currently recommended lopinavir-based second-line regimens for nonnucleoside reverse transcriptase inhibitor failures to other non-nonnucleoside reverse transcriptase inhibitor regimens head-to-head.

CONCLUSIONS

We found no evidence comparing current World Health Organization-recommended second- and third-line ART regimens with regimens including drugs of interest: raltegravir, darunavir, etravirine and atazanavir. Randomized controlled trials or prospective cohort studies with comparator arms, and bridging studies, ideally conducted in resource-limited settings, are required to guide future recommendations.

Darunavir: A Review in Pediatric HIV-1 Infection

Darunavir (Prezista®), administered in combination with ritonavir and background antiretroviral therapy, is approved in the USA and the EU for the treatment of HIV-1 infection in pediatric patients aged ≥3 years. Ritonavir-boosted darunavir provided effective virologic suppression in treatment-naïve adolescents with HIV-1 infection, according to the results of the noncomparative, phase II DIONE trial. Ritonavir-boosted darunavir also had sustained efficacy in treatment-experienced children and/or adolescents with HIV-1 infection, according to the results of the noncomparative, phase II DELPHI and ARIEL trials. Ritonavir-boosted darunavir was generally well tolerated in pediatric patients with HIV-1 infection. Although more data are needed in pediatric populations (particularly data comparing darunavir with other antiretroviral agents), ritonavir-boosted darunavir is an important option for the treatment of pediatric patients with HIV-1 infection.

A review of the toxicity of HIV medications

Antiretroviral therapy has changed human immunodeficiency virus (HIV) infection from a near-certainly fatal illness to one that can be managed chronically. More patients are taking antiretroviral drugs (ARVs) for longer periods of time, which naturally results in more observed toxicity. Overdose with ARVs is not commonly reported. The most serious overdose outcomes have been reported in neonates who were inadvertently administered supratherapeutic doses of HIV prophylaxis medications. Typical ARV regimens include a "backbone" of two nucleoside reverse transcriptase inhibitors (NRTI) and a "base" of either a protease inhibitor (PI) or nonnucleoside reverse transcriptase inhibitor. New classes of drugs called entry inhibitors and integrase inhibitors have also emerged. Older NRTIs were associated with mitochondrial toxicity, but this is less common in the newer drugs, emtricitabine, lamivudine, and tenofovir. Mitochondrial toxicity results from NRTI inhibition of a mitochondrial DNA polymerase. Mitochondrial toxicity manifests as myopathy, neuropathy, hepatic failure, and lactic acidosis. Routine lactate assessment in asymptomatic patients is not indicated. Lactate concentration should be obtained in patients taking NRTIs who have fatigue, nausea, vomiting, or vague abdominal pain. Mitochondrial toxicity can be fatal and is treated by supportive care and discontinuing NRTIs. Metabolic cofactors like thiamine, carnitine, and riboflavin may be helpful in managing mitochondrial toxicity. Lipodystrophy describes changes in fat distribution and lipid metabolism that have been attributed to both PIs and NRTIs. Lipodystrophy consists of loss of fat around the face (lipoatrophy), increase in truncal fat, and hypertriglyceridemia. There is no specific treatment of lipodystrophy. Clinicians should be able to recognize effects of chronic toxicity of ARVs, especially mitochondrial toxicity.

Comparative Effectiveness of Darunavir 1,200 mg Daily and Approved Dosing Strategies for Protease Inhibitor-Experienced Patients

Background. HIV protease inhibitors exhibit concentration-dependent viral inhibition. Higher once daily doses of darunavir boosted with ritonavir (DRV/r) may achieve viral suppression in place of twice daily dosing. International antiretroviral adherence guidelines recommend once daily regimens whenever possible. We present data on virologic suppression achieved with DRV 1,200 mg and ritonavir 100 mg once daily compared to approved DRV regimens. Methods. This retrospective observational study included all patients treated with DRV after documented use of another protease inhibitor at an urban immunodeficiency clinic. Data collection from inception of DRV use in August 2006 through March 2012 included patient demographics, viral loads, CD4+ cell counts, and resistance test results. The primary outcome of virologic suppression was defined as <50 copies/mL at 24 weeks. Differences in baseline characteristics and virologic outcomes across dosing groups were analyzed via one-way analysis of variance. Results. One hundred and thirty-five patients were included in the ITT analysis. Most patients had no known DRV RAMs at baseline. Virologic suppression rate was not different among treatment groups: 53.6% of patients on 1,200 mg daily, 52.3% on 600 mg twice daily, and 42.9% on 800 mg daily (P = 0.568). Conclusions. Darunavir 1,200 mg daily should be investigated for use in protease inhibitor-experienced patients.

Pharmacotherapy of pediatric HIV infection

The delivery of safe and effective antiretroviral therapy to children and adolescents is crucial to save the lives of millions of children worldwide. The immunologic response to human immunodeficiency infection is closely related to a child's development and creates age-specific parameters for the evaluation of therapeutic response to antiretroviral therapy. Similarly, the development and maturation of organ systems involved in drug absorption, distribution, metabolism, and elimination determines significant changes in the pharmacokinetics of antiretroviral drugs throughout childhood. The authors review the evolution in treatment of pediatric HIV from infancy through adolescence.